This present invention solves the problem of providing accurate primary instrumentation for the measurement of the velocity of a projectile. When measuring muzzle velocity, (e.g., a velocity associated with a projectile fired from a rifle or an artillery or mortar launcher), many variables affect the measurement. Examples include barrel wear, propellant temperature, unique propellant burn rate, and air density. While some of these variables can accurately be accounted for individually, when taken in total, it is most efficient to simply measure the muzzle velocity and apply a correction factor to all subsequent firings. Overall, most approaches start with the same premise of detecting the projectile over a measured distance and calculating a time period of travel to resolve velocity.
Radar systems presently are used to analyze a ballistic path but do not provide an actual point of exit measurement (i.e., from the muzzle). Other existing prior art methods comprise the use of various inductive, optical, fiber optic strain gauges, and RF injection to obtain the muzzle velocity of a non-specific barrel guided projectile. The inductive approach exhibits a characteristic reduced frequency response while optical and fiber optic systems are not suitable to the combat environment or are not practical for fielding. RF injection requires that the barrel be penetrated at multiple locations which violates the military standard for barrel structural integrity.
Another, more accurate technique is described in U.S. Pat. No. 7,082,823. Hall effect integrated circuit sensors with pre-conditioned digital signal processing (DSP) are used to accurately produce a time over distance variant function of a projectile. Hall Effect sensors, however, due to their inherently low amplitude signal output derived from the Hall effect, restrict the usable measurement range of a velocity measurement system. For example, while a Hall Effect sensor is effective at measuring projectile velocity in mortar applications, it is less effective or not effective at all for measuring velocity in artillery applications.
Therefore, it is desirable to provide high resolution sensors that enable a broad spectrum of projectile velocities to be measured.